Disable "Check for Updates" UI in Portable Firefox?

By default, Portable Firefox checks for updates from Mozilla. If a user accidentally applies a Mozilla auto-update to his Portable Firefox, this breaks the portable-ness because Mozilla's updaters typically touch the registry etc while installing.

This has actually happened to me once, and left my Windows complaining that the default browser in U:\Internet\Firefox\App\Firefox could not be found when I removed the USB drive. *sheepish*

I was wondering if it might not be better to disable update checking for Portable Firefox. I have done the below for my installation but am sure others would benefit if this was part of the default.

In user.js -

// don't auto-update Firefox, this breaks Portable-ness
user_pref("app.update.enabled", false);

And to prevent users from shooting themselves in the foot with Help | Check for Updates...

In userChrome.css -

/* remove the Check for Updates menu item */
#updateSeparator, #checkForUpdates { display: none !important; }